What AR lowers to avoid?

skeetlee

Gunny Sergeant
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Minuteman
Jun 13, 2008
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Central Illinois
I hate to ask but i am going to start buying parts to build a varmint AR. I notice that there are some pretty cheap stripped AR lowers on the market. Are there any that need to be kept away from? Parts kits also? If you think its in better taste, please just send me a PM with the info. thanks Lee
 
Re: What AR lowers to avoid?

I have bult a lot. I would stay away from cast lowers. And any of the polymer lowers out there. Any good std. Forged lower or billet will work great. Good quality parts kits can be had from RRA, DPMS or Bushmaster. Most people will get a quality aftermarket triger. So you are looking at just the pins and springs. Etc. Most are very much alike.
 
Re: What AR lowers to avoid?

As best i can think of there really aren't any bad lowers anymore. No one i can think of makes cast lowers (stay away from th plumb crazy plastics) anymore and most the mil spec 7075 ones are made by only a few different folks. Really the price difference is over more desirable roll marks. The same goes for lpks. For those it mostly comes down to QC since again most come from the same supplier.

 
Re: What AR lowers to avoid?

Why do you guys recommend staying away from polymer lowers? I was looking at one the other day but wanted to hear some first hand experience. Did you guys have one that cracked?
 
Re: What AR lowers to avoid?

I've only had one lower of the six I've bought not be within spec. It was made by Roggio, IIRC, and was not the least expensive lower I've bought. Sometimes you get what you pay for, but often times with lowers, it's like Starvin said, it's mostly about the roll mark these days.
 
Re: What AR lowers to avoid?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ultraman550</div><div class="ubbcode-body">Why do you guys recommend staying away from polymer lowers? I was looking at one the other day but wanted to hear some first hand experience. Did you guys have one that cracked? </div></div>

Id be wary of the area around the pins eventually fracturing/cracking with a polymer lower.
 
Re: What AR lowers to avoid?

When picking out a lower make sure mags will drop free from the magwell and that you have all the correct holes in the proper place, and no funky cuts or incomplete milling anywhere. Other than that, roll marks are personal preference.
 
Re: What AR lowers to avoid?

I hear some lowers wont fit certain magazines, or some magazines wont fit certain lower mag wells. Thats kinda what i was concerned with. Anyone have a lower to sell? I am going to build a varmint Ar one piece at a time. should be fun. Lee
 
Re: What AR lowers to avoid?

Not all Polymer lowers should be avoided. The issue I see with the plum Crazy lower is not the pin area, but were the Buffer tube attaches to the receiver. this can be a stress point...well, more of the neck area below the buffer tube and behind above the take down pin. If you just want a very light rifle and to not plan on shooting tens of thousands of rounds through it.....

I have a LOT of experience with the Cavalry Arms polymer lowers (no longer in production, but the Mold is for sale). I have put 100,000s of thousands of rounds through those lowers. I had a personal full auto Cav Rifle that had atleast 50K through it. I parked my old truck on it, took pictures, and used it for years after. I have even shot a Beowulf on full auto on a Cav Lower. The advantage of the Cav MKII design is the one piece receiver, grip and stock design. It is molded in two pieces and vibration welded together. so any part that touches the other side fuses together, to the point, the weld is strong then the rest.

Receivers to stay away from: Hesse/Vulcan or whatever the current name is that he is manufacturing under. That is the only one I have ever had issues with.
 
Re: What AR lowers to avoid?

Superior Arms. Stay far away. I would normally support a fellow home state manufacturer but these things are so far out of wack it is unreal. They sent me 3 of them before I finally said to keep it an give my $ back. Twisted, tool marks everywhere. Holes too big, an holes too small. And them say they are Milspec.
 
Re: What AR lowers to avoid?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: skeetlee</div><div class="ubbcode-body">Let me say this. I do want to use the plastic P-Mags. I guess i should probably just buy a rock river and be done with it? Lee</div></div> if not changed use of pmags and spikes is a bad mix .....ban years of bushmaster, a bit loose ..
 
Re: What AR lowers to avoid?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ultraman550</div><div class="ubbcode-body">Why do you guys recommend staying away from polymer lowers? I was looking at one the other day but wanted to hear some first hand experience. Did you guys have one that cracked?</div></div>

I ran about 40 rounds through a nearly new Plum Crazy lower with a Slidefire stock (OK, go ahead and flame me. I deserve it).

The polymer pins sheared. I left a message on Plum Crazy's machine to give them the heads-up, but never heard back.

Another negative is that it won't drop any of a half-dozen types of mags I tested.

On a positive note, the trigger feels crisper than a new Colt and for $120.00 you get the complete lower with stock and all internals.

 
Re: What AR lowers to avoid?

Many lowers are produced by the same few manufacturers, however each individual company has their own order specs, and their own quality control measures. There are some big-name companies like DPMS and Bushmaster that have a higher instance of parts being out of spec than companies like Rock River, CMT/Stag, Spikes Tactical and S&W. Then you have the lowers which are pretty much guaranteed to always be in-spec, like BCM, LMT, Noveske, VLTOR, KAC, Colt, LaRue, Mega, Seekins, etc.

As stated above, if you stick with forged or billet, you'll generally be okay. Just be sure to stay with an established company.
 
Re: What AR lowers to avoid?

Im a big JD machine fan I own one and have had experience with several others and they are of great quality. Plus the guys that run the place are great to deal with.
 
Re: What AR lowers to avoid?

They are <span style="font-style: italic">essentially</span> all the the same.
However, there may be good reasons to choose one over another.
The biggest reason is cosmetic and how it fits to a particular upper.
Another reason for most is the "name".
Billet vs forged can be debated but they both do the same job.
A $59 Forged will do the same job as a $200 Billet.
There are only a handful of manufacturers that make them for everybody.
 
Re: What AR lowers to avoid?

Colt LPK's suck. I couldn't find any other so I got the Colt from Brownells. There was no safety, and the front pin had a screw in the other end that you had to take out in order to swap lowers.
 
Re: What AR lowers to avoid?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JD42</div><div class="ubbcode-body">I have bult a lot. I would stay away from cast lowers. And any of the polymer lowers out there. Any good std. Forged lower or billet will work great. Good quality parts kits can be had from RRA, DPMS or Bushmaster. Most people will get a quality aftermarket triger. So you are looking at just the pins and springs. Etc. Most are very much alike. </div></div>

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